The present invention relates generally to construction materials and processes; and more particularly, it relates to the electrodeposition of minerals to form a material suitable for use as a coating and filler of wood and other like materials to inhibit biodegradation of such materials.
Seawater contains nine major elements: sodium magnesium, calcium, potassium, strontium, chlorine, sulphur, bromine and carbon. These elements comprise more than 99.9% of the total dissolved salts in the ocean (see Milliman, et al., Marine Carbonates, Springer-Verlag, N.Y., 1974; Sverdrup, et al., The Oceans: Their Physics, Chemistry, and General Biology, Prentiss-Hall, Inc., in N.J. 1942; and Culkin and Goldberg in Volume 1, Chemical Oceanography, pp. 121-196, Academic Press, London 1965). The constancy of the ratios of the major elements throughout the oceans has long been well-known (Dittmar, Challenger Reports, Physics and Chemistry, pp. 1-251, 1884).
In 1940 and 1947, G. C. Cox was issued U.S. Pat. Nos. 2,200,469 and 2,417,064, outlining methods of cathodic cleaning and protection of metallic surfaces submerged in seawater by means of a direct electrical current. During the cleaning process, a coating is also formed cathodically, consisting of magnesium and calcium salts (Eichoff and Shaw, Corrosion, No. 4, pp. 363-473, 1948). If these coatings are hard and continuous, they afford a considerable degree of corrosion protection to the enclosed metal (see Humble, Corrosion, No. 4, pp. 358-370, 1948, and Corrosion, Volume 4, No. 9, pp. 292-302, 1949).
Lower marine organisms utilize the minerals in solutions surrounding them to build structural formations. Mollusk shells, for example, are generally composed of calcium carbonate crystals enclosed in an organic matrix. A significant proportion of the soluble protein in the matrix is composed of a repeating sequence of aspartic acid separated by either glycine or serine (see Jope in Volume 26, Comprehensive Biochemistry, p. 749, Elsevier, Amsterdam, 1971). This sequence, comprising regular repeating negative charges, could bind Ca.sup.2+ ions and thus perform an important function in mineralization of the template (Weiner and Hood, Volume 190, Science, pp. 987-989, 1975).
Although impressed current-produced calcium carbonate/magnesium hydroxide formations are known, such formations have never been thought of as primary coatings and/or mineralizing materials on and in a structure of wood or other organic fibrous/porous material with the intent to prevent biodegradation in seawater, or on land, and to strengthen the material.